title: Assessment of aerobic capacity and walking economy of unilateral transfemoral amputees.
abstract: BACKGROUND
  Studies of the maximal oxygen uptake (VO(2max)) of transfemoral amputees have mostly used protocols that activate a relatively small muscle mass. Consequently, transfemoral amputee VO(2max) may be systematically underestimated, and the validity of these test protocols is questionable.
  
  
  OBJECTIVE
  (1) Investigate validity and reliability of a VO(2max) walking protocol and (2) compare the VO(2max) of a transfemoral amputee group with a group of matching controls.
  
  
  METHODS
  (1) Randomized crossover study: walking versus running VO(2max) for the control group and (2) case-control study: transfemoral amputees versus control group VO(2max).
  
  
  METHODS
  Twelve transfemoral amputees and control participants performed a walking VO(2max) test with increasing treadmill inclinations to voluntary exhaustion. The control group also completed a running ("gold-standard") VO(2max) test.
  
  
  RESULTS
  Mean (standard deviation) control group VO(2max) following walking and running was similar, that is, 2.99 (0.6) L min(-1) and 3.09 (0.7) L min(-1), respectively. Mean (standard deviation) transfemoral amputee walking VO(2max) was 2.14 (0.8) L min(-1) (compared to CON; p < 0.01). Mean intraclass correlation coefficient of repeated VO(2) measurements was 0.97, and within-subjects standard deviation was 60 mL min(-1).
  
  
  CONCLUSIONS
  The walk protocol is valid. Walking VO(2max) of transfemoral amputees was 40% lower compared to control group. Reliability of the walking protocol is comparable to other walking protocols. Clinical relevance The design, alignment, and materials of prostheses are important for effective ambulation. Cardio-respiratory fitness is, however, also important in this regard, and a low fitness may compromise health and independent living. Hence, transfemoral amputees with low physical fitness should engage in regular physical activity to improve health, gait capacity, and independency.
authors.affiliation: 1Faculty of Health Science, Oslo and Akershus University College, Oslo, Norway.
authors.forename: Terje
authors.initials: T
authors.lastname: Gjovaag
authors.forename: Inger M
authors.initials: IM
authors.lastname: Starholm
authors.forename: Peyman
authors.initials: P
authors.lastname: Mirtaheri
authors.forename: Fride W
authors.initials: FW
authors.lastname: Hegge
authors.forename: Katrine
authors.initials: K
authors.lastname: Skjetne
mesh_terms: D000328:Adult; D000674:Amputees; D001186:Artificial Limbs; D016022:Case-Control Studies; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005269:Femur / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D011474:Prosthesis Design; D015203:Reproducibility of Results; D013997:Time Factors; D016138:Walking / Q000502:physiology*
keywords: Energy expenditure; VO2max; gait; preferred walking speed